求助什么是D8+ certification大

ychych512：求助什么是D8+ certification
大家好，有个客户回我的一句客户，很伤心。
Sorry, are D8+ (plus), not C8+; you have to look in internet!
But if you don't know what are D8+ certification, we think your product not are good for the european market!!!!!!
产品是STAGE HOIST， 有哪位大侠知道这个D8+ certificate, 请赐教。
THANK YOU VERY MUCH